Gradually, this system became widespread among all users of surface water in Colorado and was referred to as the Doctrine of Prior Appropriation, or the First-in-Time, First-in-Right doctrine. 
The first rules regarding the use of western surface water originated in California during the Gold Rush of 1849 and were brought to Colorado during the Gold Rush of 1859.
Any miner who used the water first had the right to use that water over any miner who arrived later. The next miner to arrive and use water had the right to use water over anyone arriving later, but had to defer to anyone with an older claim to water.
Gradually, this system became widespread among all users of surface water in Colorado and was referred to as the Doctrine of Prior Appropriation, or the First-in-Time, First-in-Right doctrine. The right to the use of water and land ownership did not go hand in hand because much of the surrounding land was federally owned. However, the water itself was considered property.
In 1876, the Doctrine of Prior Appropriation was set forth in the Colorado Constitution.
To obtain a water right, water must be put to a beneficial use. The Constitution recognized a preference of water uses in the following order: domestic, agricultural, and industrial. Water rights may be bought, sold, inherited, moved from one place to another, or changed from one type of use to another, as long as the change does not injure other water rights.In 1957, tributary ground water (ground water that is connected to a stream) became subject to the Doctrine of Prior Appropriation under the Ground Water Management Act.
